The pathology about fluid qi of three cavities is completely analysed in this paper,the malfunction up-down that the fluid qi of three cavities stagnates at nose hole is the important micro-mechanism of the nasosinusitis pathology,this shows that the strengthened“yang”change to“qi”and drainage is very important therapy and contributes a new way to nasosinusitis therapy.A treatment case shows the therapy of the strengthened“yang”change to“qi”and drainage is very important to nasosinusitis.